Gas turbines, such as aircraft engines for example, are made up of multiple subassemblies, namely a fan, preferably multiple compressors, a combustion chamber, and preferably multiple turbines. For improving the efficiency and the working range of such gas turbines it is necessary to optimize all subsystems or components of the gas turbine. The present invention relates to the improvement of the efficiency and the working range of compressors, in particular transonic high-pressure compressors.
As a rule, compressors of gas turbines are made up of multiple stages, which are situated axially consecutively in the flow, each stage being formed by a rotating blade row formed by rotating blades assigned to a rotor. The rotating blades forming the rotating blade row and assigned to the rotor rotate together with the rotor vis-á-vis the stationary guide blades and a likewise stationary housing. For reducing manufacturing costs, an increasingly compact compressor design having the lowest possible number of stages is aimed for. Furthermore, the overall pressure conditions within the gas pressure turbine or the compressor and thus the pressure ratios between the individual stages increase due to the constant optimization of the efficiency and the working range of such compressors.
Increasingly larger stage pressure ratios and an increasingly smaller number of stages inevitably result in higher circumferential velocities of the rotating components of the compressor. The rotational speeds, which increase with the reduction of the number of stages, result in increasing mechanical stresses in particular on the rotating blades rotating together with the rotor and in a supersonic flow over the rotating blades as well as in transonic flow conditions within the blade grid.
Such flow conditions require an optimized, aerodynamic design of a compressor; in such an aerodynamic design, attention must be paid in particular to accurate contouring of the blade profiles and the leading edge of the blade.
For influencing the stability behavior of a fan and thus for optimizing the efficiency and the working range of same it is known from the related art to slant the fan blades of a fan in the area of its leading edge in the sense of a sweep angle. A distinction is made between fan blades whose leading edges are slanted in the sense of a forward sweep and such rotating blades whose leading edges are slanted in the sense of a backward sweep. Reference is made in this regard to U.S. Pat. No. 5,167,489.